3. Results
3.1 Carcass features and information collected on
site
The adult female weighed 3.62 kg, with a body length of 68.2 cm, tail
length of 29.4 cm; the female kitten weighed 2.62 kg, with a body length
of 60.3 cm and tail length of 27.2 cm. Compared with the kitten, the
adult clearly showed worn palm pads, claws and a greater tooth wear
(especially canine teeth) (Fig. 3a, b). Both the carcasses showed a
severed cervical spine caused by a carnivore bite, with fracture in
C3-C5 of CMC-1 (Fig. 3c, d), while the occipital bone was dislocated
from C1 for CMC-2 (Fig. 3e, f). Other than these fatal injuries, no
other health issue was detected. This suggested that the spinal injury
was the cause of death.
The body of the female kitten (CMC-1) was found right beside the farm of
a local herdswoman on 30 Jan 2019. She reported that in the night of 29
Jan, when she was driving the yak herd back, she saw her dog chase the
cat into its hiding burrow and bark in front of it. In the next morning,
she found the dead body of the cat beside its den and, later, her dog
dragged the dead cat approximately 50 m away from its burrow (Fig. 1b).
On 7 Feb, the body of the adult female was also found beside its hiding
burrow and similar description was also collected for it (Fig. 1b). One
local herdsman reported that, two days before, stray dogs chased the
adult female not far from where the body was found on 7 Feb. Based on
our camera trap monitoring since Sept. 2018, no wild predators in
Gyatong capable of killing the cats (e.g., lynxes, wolves, bears) have
been recorded in the area. Therefore, all the evidence suggested that
free-ranging dogs were responsible for the death of both cats.
3.2 Free-ranging dogs
survey
Overall, 15 valid questionnaires were collected in Gyatong. The survey
and interview suggested that there were two kinds of free-ranging dogs
in the area: unchained domestic dogs and homeless stray dogs. In total,
166 domestic dogs were recorded in the Gyatong Grassland. Among them, 27
domestic dogs and seven stray dogs were found roaming in the range of
the Chinese mountain cats (Fig. 4).
With respect to the rearing methods for the domestic dogs, all the
interviewees suggested that they would chain their dogs in the daytime
when there was someone home. However, domestic dogs would be set free at
night or when the owners left home. No dogs are vaccinated. No dog
abandonment was reported. There were also no cases of hybridization
between domestic dogs and stray dogs according to the herdsmen. All the
interviewees suggested that the number of stray dogs were increasing in
recent years. When being asked about the potential origin of stray dogs,
the locals suspected that they wandered here from Sichuan province.
In terms of attitudes towards stray dogs, most local herdsmen claimed
that they were unaware of stray dogs’ predation on wildlife, yet showed
high tolerance of such behaviors when informed. They were not averse to
the
capture of stray dogs so long as the dogs were not killed
on-site
and the control measures had no effect on domestic dogs.
3.3 Genetic analysis of
carcasses
Taxonomic status of the Chinese mountain cat is controversial and a
recent genomic study suggested an alternatively classification as a
subspecies (F. silvestris bieti ) in wildcat conspecifics (Yuet al. , 2021), which we followed in the genetic analysis.F. s. bieti , F. s. ornate and F. s. silvestris were
separated into three distinct lineages, and F. catus and its wild
ancestry F. s. lybica formed one more lineage in the
mitochondrial phylogeny. Both our Chinese mountain cats and hybrid
kitten samples were clustered in the lineage of F. catus +F. s. lybica (Fig. 5a). Genotyping of nuclear loci showed that
seven of the eight autosomal loci and all the three X-chromosomal loci
for CMC1 and CMC2 were homozygous F. s. bieti genotype, while
only one locus was homozygous F. catus genotype (Table 1). Those
results indicated that the vast majority of the genome in this cat
family originates from the Chinese mountain cat. However, domestic cats
are identified as at least one of their maternal predecessors. The
genotype of CAT1 and CAT2 was 4 homozygous F. catus loci, 1
homozygous F. s. bieti locus and 3 heterozygous loci on autosome,
and 2 homozygous F. catus loci and 1 homozygous F. s.
bieti locus on X chromosome (Table 1). The Y loci of male CAT2 wasF. catus genotype. The genetic compositions of the two ancestral
species are both considerable, as ~70% from the
domestic cat and ~30% from the Chinese mountain cat.
However, the fact that they have homozygous genotype from both ancestral
species suggested that the hybridization in this pedigree had happened
for multiple generations.